An Evaluation Tool for Audible Scanning User Interfaces

Background

Cerebral palsy is a condition that causes varying degrees of motor
impairment. The most severely affected of cerebral palsy users
communicate using a large button, called a switch, connected to a
computer. Using a technique called switch
access scanning, the computer browses through various options
automatically, and the user presses the switch when the option they
want is selected. The switch can also be used to determine how much
motor control a user does have, by seeing how quickly they respond
when told to select a specific option.

For many users with cerebral palsy, supporting
their heads for a long period of time is difficult. Compounding the
situation, many also have cortical visual
impairment, a form of visual impairment that results from damage
to or defects in the brain. Because visual function can change from
day to day and even from minute to minute in users with cortical
visual impairment, it can be particularly difficult to evaluate these
users’ cognitive and motor function.

A number of programs are already available for use with the
switch. However, for all of these programs, the user must be
looking at the screen. This can be difficult for users who cannot
support their heads for long periods of time, or who have visual
impairment.

Project

Our program functions similarly to the existing programs for
the switch. However, as the computer selects each option, it will also
play a sound corresponding to that option. This will be useful to
occupational therapists to distinguish between a user who has poor
motor control and a user who cannot see the screen. In the future
this could be adapted to help cerebral palsy users and others with
similar disabilities to communicate their wants and needs.

Our game has two parts. The first part is a simple
cause-and-effect game to help the users understand that the switch
has an effect. The user will be instructed to press the switch to
play a sound, and every time the user does so, a reward sound will
be played. Once users seems to understand that pressing the switch
causes the sound to be played, he or she can move on to the next
game.

The next game is a linear scanning game. Linear scanning is an
important tool used by occupational therapists to asses cognitive
function in users with Cerebral Palsy. As the computer scans
through different options, a corresponding sound is played, and the
user presses the switch when the option they want is selected.

The impact of adding these sounds upon the program’s usability is
tremendous. With the addition of a relatively small number of sound
files, the program becomes usable without any visual prompting
whatsoever. Theoretically, this program could even be used to evaluate
a patient who is completely blind. This is a large step toward
accommodating patients who may have good cognitive function, but whose
physical function is limited by their vision.